Improved sensitivity of gold nanoclusters toward trypsin under synergistic adsorption of CdTe quantum dots

Abstract

Many physiological and pathological processes are associated with trypsin, so the sensitive detection of trypsin is significant for exploring these processes. Herein, AuNCs/CdTe QDs as the complex of bovine serum albumin-capped gold nanoclusters (BSA-AuNCs) with 3-mercaptopropionic acid-stabilized CdTe quantum dots (MPA-CdTe QDs) were prepared via electrostatic assembly for sensitive determination of trypsin through synergistic effect. In AuNCs/CdTe QDs, the red luminescence of BSA-AuNCs kept almost unchanged, whereas the green luminescence of MPA-CdTe QDs disappeared because of the static quenching process. Once trypsin was added to AuNCs/CdTe QDs, the structure of BSA-AuNCs was frustrated ascribed to the hydrolysis ability of trypsin toward BSA, causing the red luminescence of BSA-AuNCs to quench, moreover the electronic attraction of MPA-CdTe QDs toward trypsin facilitated the hydrolysis of BSA. The detection sensitivity of AuNCs/CdTe QDs for trypsin was therefore promoted under the synergistic adsorption of MPA-CdTe QDs, and the detection limit of trypsin with AuNCs/CdTe QDs was determined as low as 12 ng mL−1 (0.50 nM). AuNCs/CdTe QDs were employed to the measurement of trypsin in urine samples, and the result indicated that spiked recoveries ranging from 80.0 % to 119 % were acquired, offering a reliable tool to explore the relevant physiological and pathological processes.